More than 96% of the alumina which is produced worldwide is obtained from bauxite, which is a mineral that is particularly rich in alumina (40-60%) and whose main suppliers are from Jamaica, Australia, Brazil, Africa and Russia. In certain areas of the world there are large quantities of aluminous ores, which are aluminosilicates (for example argillite, nepheline, etc.) that are relatively rich in alumina (20-28%). However such areas have received little attention up to now because the production costs for extracting aluminum from such ores remained too high. In these aluminous materials, and contrary to bauxite, aluminum oxide is associated with silicated or sulfated phases. Thus, the Bayer process cannot be used, which means that alternative treatments for the production of alumina must be used or developed. Various processes have been proposed so far in order to extract aluminum from such aluminous ores comprising aluminosilicates but there is still room for improvement or for alternative routes.